06tl2

So I had installed 2x Fosgate P3 12 in ported box in my TL. I had done the installation from new amp to loc to sound deadening. I had to get rid of the setup because it was too heavy and since I have gotten coil overs and new wheels my car would rub.

Now my question is that can I just use any subwoofer for Infinite baffle setup or do they have to be specific?
I am thinking

pohljm

I think your still going too rub

06tl2

Rub?
Do i need special kind of woofer to do ib? like free air? or ported will work?

justnspace

iTrader: (1)

at 52 lbs.

justnspace

iTrader: (1)

there's this cool search engine on the internet....maybe you've heard of it? Google?

its real easy to "google" IB set ups.

Let me google that for you

guitarplayer16

iTrader: (8)

pohljm

I dont even know how you do that with that link but that was awesome!

06tl2

Still couldnt find answer to if I could use the sub in original post for ib setup.

06tl2

And can you just use any kind of subwoofer? subwoofer made for ported box will work in infinite baffle setup?

justnspace

iTrader: (1)

^you can. but why do an IB set up with a heavy ass sub with the largest motherfucking magnet on the planet?

with an IB set up; you use WAAAAAAAAAAY less power for almost the same amount of sound decibels, so, you wouldnt need a big motherfucking sub.

edzyy

Rule of thumb is

Mid-high QTS
Low VAS
Low FS
Lot of Xmax

If you're on a budget look into
Pyle blue waves
JBL GTO
Boston G2
Dayton IB
Alpine Type s

You should looking for the 15's only.

SgtSir440

That earthquake sub you posted in the op is pure trash. It would be still be shit even if it was only $34.50

Yes, you want something geared towards IB. If I was going to do an IB setup I would go with one or two of these:
Dayton Audio UM15-22 15" Ultimax DVC Subwoofer 2 ohms Per Coil

Also, buy a real amp. The amp and electrical support for the amp is 90% of the equation and learn how to properly set gains if you don't already know how. I think you need to spend some time reading up on some car audio forums!!!

justnspace

iTrader: (1)

^which I tried to get him to do....but he wants us to hold his hand

edzyy

Not trash, but def not good for an IB build.

I hate cars

I wouldn't run those subs in anything. I admittedly know nothing about them but they look cheesy. Maybe I'm wrong but you don't need an expensive sub for IB.

To directly answer the original question, yes, you can run any sub IB. More specifically, any sub designed for a sealed box should work very well IB and will likely sound better than sealed.

Many subs designed for ported setups have a very strong motor but less excursion. They can still be used and can sound very good IB but output will be limited because of the reduced excursion. Remember than in IB and sealed, output is determined solely by displacement. How much cone area and how much excursion determine output. If you have two identical subs and one is sealed, the other is IB and both are moving 1", output will be exactly the same, even if the sealed sub requires 1,000w to move 1" and the IB sub requires 100w to move 1". The less power it takes to hit xmax, the better. Sealed and IB have exactly the same output potential but IB will require considerably less power to hit full output because the sub does not have to fight against the air spring. So the fact that IB won't take as much power as sealed is a good thing.

IB gives better cone control than a sealed box, not worse as many people believe. A sealed box reduces both efficiency and cone control. Some say that IB will sound sloppy because there's no air spring to control the cone but in fact it sounds tighter and better controlled because it is. This is evidenced by a lower system Q or better damping. This is part of the reason you don't need a monster sub with a huge motor.

Qts = the sub's Q in free air. Qtc = the sub's Q when installed into a box/trunk and in the car. I call Qtc the system Q and Qts the sub's Q. The higher the system Q, the less cone control there will be. This means overshoot where the signal stops and the cone continues moving. This is what makes a system sound slow, sloppy, and boomy. In a sealed box, energy is stored from the compressed or rarefied air in the box and it forces the cone to overshoot. The cone does not start and stop as quickly as it should. This will show up as slightly more output because the cone is moving slightly farther on each end but it's usually in the 50-65hz range where it's not needed or wanted. Since it is not following the signal faithfully, it's considered distortion. I don't want to gain output via distortion. The smaller the box, the less cone control there is. The more excursion, the more system Q changes for the worst. This is one more advantage of IB, the Q changes less as the volume is turned up.

Keep in mind, the motor does the vast majority of the damping or control. The suspension (spider and surround) have almost zero effect on the damping (Q). The air spring of a sealed box can be called an acoustic suspension and as described above it does have an effect on cone control, a negative effect. But the main thing to keep in mind is the motor is responsible for the vast majority of the damping, not the suspension. A stronger motor with all else being equal will give better cone control. This is why one of the myths that a sub needs a stiff suspension for IB use is false. One of the best IB specific subs out there, the IB15 that I ran for a few years had the softest suspension of any sub I've ever run. I literally had to check the spider when I first got them to make sure it wasn't defective, torn, or not attached. The cone was super easy to push in. The spider's job is to center the voice coil and the surround is to center the cone and keep it air tight.

There are a couple things I do not agree with, I hope I don't offend anyone.

You absolutely don't need to use a sub with a mid to high Qts. Qtc is what counts. Since car IB is not true IB due to the fact that the trunk has a small effect on the subs, the system Q (Qtc) will go up somewhat when the subs are installed. Real IB such as when the sub is installed with a large room to vent into, Qts = Qtc. There is no effect of an enclosure/air spring in a large enough room or attic or basement as people commonly vent their home theater IB setup to. If you start with a .7 Qts you can easily end up with too high of a Qtc and a sub that sounds boomy, sloppy, and slow, and wont' want to dig low without lots of power. In fact, my IB specific subs had a .46 Qts and the design goal was to have a .6-.7 Qtc once installed. The Vas, the size of the trunk, and the number of subs (Vas x 2) will determine how much Qts raises once installed.

My personal preference is a target Qtc of .5 and no higher than .6. This gives a very tight, controlled, and more accurate bass. .5 is considered critically damped. The sub has no overshoot and it's true to the input signal. There's no boominess. In fact, I prefer this by a mile to a .7 or greater Qtc.. Many people are beginning to do the same, some don't even realize it. One of the best sounding subs out there, the Dynaudio 1200 has a Qts of .3x. People love those subs IB and in the Dyn's case, Qts = Qtc. The very best I've ever heard was my JL 12W6 in an infinite baffle setup. It had a Qts of .46 and due to the Vas being low, Qts = Qtc in that setup. It made me not want to get out of the car it had so much punch, it was so tight, so accurate, and it dug so low so smoothly. It was a single 12" but it got plenty loud.

That brings me to my next point. You absolutely don't have to run 15s. IB has the same output potential as sealed so if a single 12" sub is enough for you sealed, it will be plenty IB. The main difference is the sub will be more efficient on the low end when IB so it will have more excursion on low notes. It can run out of excursion and bottom out but that's easily fixed by adjusting the subsonic filter on the amp. If you want a sound quality system that you play moderately loud sometimes, a single 12 will work. To go one octave lower in frequency requires double the displacement. So say your sealed sub system only dug down to 40hz with any authority and your new IB setup digs to 20hz with authority which is common, you're going to need double the excursion to hit 20hz at the same output as 40hz. This is why people suggest multiple larger subs when going IB, because it's capable of hitting such lower notes with authority.

I suggest multiple larger subs when possible because there's no real downside when using them in an IB config. You don't have to worry about the huge box size or weight. Larger subs, with all else being equal will give more output, lower distortion, higher efficiency, and the T/S parameters are usually a little better in regards to sound quality. Bigger is literally better in every possible way. But again, if you're looking for a sub to blend in with the fronts, the fill in the low end that will get loud enough to have a little fun once in a while, a single 12" will work just fine.

I currently run a pair of IDMax 15s. I got them because of the huge cone area (935cm^2 which is more than any 15" sub I've been able to find by a good margin). 28mm linear one way excursion, 50mm one way mechanical excursion. They use a 10" spider and a 2.5" VC and the surround is huge. Suspension wise I have no doubt they can do 4" of total travel. ID needs to get their crap together because a lot of their specs are wrong but from WinISD, they have a Bl of 16tm, not the rated 10 or 11tm. Moving mass is 320g which is a spec they don't publish but it's fairly light given the size. I don't know what inductance is but these things are incredibly capable in the midbass range and have no issues playing vocals and sounding decent doing so. I have to assume inductance is at least somewhat low. Again, they don't publish inductance because they probably don't know how to measure it but that's a different thread.

So what I've gotten with a pair of large 15s with high linear excursion is a system that when it's played at normal volumes and where the subs don't stand out but they blend in nicely with the fronts which is 95% of the time, the subs can't be seen moving. Excursion is no more than 1-2mm. This means very low distortion. For reference to the many people with a single 10" sub in a sealed enclosure like the side enclosure guys, their subs would need 12mm of excursion for the same output which is near xmax for most 10s. The 15s are going to have far less distortion. Then imagine you decide to have some fun and really crank them up. Mine with about 15mm one way excursion is pretty damn loud. The popular single 10" setup would require 90mm excursion one way which no sub is capable of. Since xmax is 28mm on these subs, 15mm is still low distortion and easy for them.

So yes, multiple large subs are "better" but if you want a nice SQ system and you don't have a lot of bass head DNA but you like to have fun with it occasionally, your favorite sealed box 12" sub will do just fine.

I look for a setup that has the lowest possible Fs (resonant frequency), something that will give ~.5-6 Qtc installed, and lots of cone area and at least decent xmax. I put cone area above excursion because cone area increases efficiency while it can take significant power to push a sub to high excursion. What I would avoid like the plague is a high resonant frequency, say > 40hz, or a Qts of .7 or higher. These two things are the only things I would not do. Everything else can work.

Don't forget that by adding a second sub with the same power (single getting 300w, pair getting 150w each), you still gain 3db which is the equivalent to doubling your power. That's another good reason for going with a pair.

So just about any sub will work and will more than likely sound good. There's no such thing as an "IB" sub. Be careful of subs designed for home IB, the Qts and Vas will likely be too high for car use.

I recommend the JL 12 and especially 13W6 if you want an absolutely amazing sub setup. A pair of 13W6s will get loud if you can still find them. The ID Max15 sounds extremely good. I would use them even if it weren't for their crazy output. They sound better than the highly recommended IB15s I used to run and for some reason they sound completely different and way better than their smaller ID Max siblings. The Incriminator Audio does very well. The IDQ subs sound very good and output is ok. The IB15 and SBP15 sound great and only weigh 17lbs to 25lbs. If you have the money, they Dynaudio Esotar 1200 sound very, very nice but you might end up wanting at least two. They have pretty low cone area for a 12" sub.

I believe the ultimate sub is the Acoustic Elegance Av15. It is just awesome in every possible way. Ultra low inductance, great suspension especially compared to their cheaper IB15 and SBP15 siblings, great excursion (23mm one way linear and 32mm one way mechanical). The cone is less than 2/3 the weight of the IDMax 15, the efficiency is very high for a car audio sub, they literally require just under half the power for the same output as my Max 15s and most other car audio subs, the cones are now structural aluminum so no folded cones, they're all made by the owner, machined by hand at his facility, he makes the surrounds in his own hydro former, he sews in the power leads by hand, and they're tested near full mechanical excursion for 24 hours so any defects will be seen before they ever get shipped out. Resonant frequency is in the low 20s, Qts is very low, around .3 and for a pair in the trunk it comes out to .45 which is exactly what I want. They're under $500 which sounds expensive but when you consider the features, what you're getting which I barely scratched the surface and considering the $1,500 subs it competes with do not have half the features, they're a bargain. I'm totally satisfied with my Max 15s, I consider them one of the ultimate IB subs and one of the best I've ever heard but I think I'm going to sell them and get the AV15s just because I can't help myself.

Hopefully I did not confuse you even more. Basically, run your favorite sealed box sub, especially if they make a 15" version. You probably don't want to go less than a single 12". If the sub runs out of displacement and bottoms, you simply turn on and adjust the subsonic filter to stop it from bottoming.

People make a big deal out of getting the perfect specs for IB subs but in reality, IB is much more forgiving than sealed is, it's harder to screw up on sub selection. With that said, it's not often you see people worrying about getting the perfect sub for their sealed box and things usually turn out fine though I suspect most are running around with their subs in a much too small box and they're not realizing what theyr'e missing. Nothing will give you that low and even subsonic bass like IB will. It's an almost overwhelming feeling when you first play a pipe organ through an IB system with lots of displacement.

After going IB, I will never go sealed again. If my car/truck doesn't allow IB, I will use a ported box. In my opinion, sealed is a last resort. It's main upside is convenience and that's about it. Both IB and ported offer considerable advantages over sealed with ported likely being the best at several things if done right.

pohljm

IHC you know you want my Blue Wave!

I hate cars

I would love to try them.... Seriously. I'm looking for something to put in my new 328i.

I was talking to another member about IB and I reminded myself about a setup I want to try so incredibly bad and it might be perfect for the Bimmer.

The JL TW-5 13.5". It's 2.6" deep. Great IB specs. Only 11mm linear excursion but 25mm xmech and almost the cone area of a small 15". A pair would get plenty loud and only take up 2.6" of trunk space. You probably wouldn't even notice them. 50lbs total weight gain including the baffle. Just an amazing potential setup for a near zero compromise setup for a daily driver than needs trunk space.